Fluid-degassing system

ABSTRACT

The system removes gases and moisture from dielectric fluids such as, for example, insulating oils normally used to provide electrical insulation between electrical components in a tank filled with such dielectric fluid. Degassing occurs in a treatment reservoir into which the fluid is initially introduced and such degassing is accomplished using a combination of vacuum and ultrasonic vibration and also, in some instances, the fluid may be heated in the reservoir to a sufficiently high temperature to assure efficient liberation of moisture from the fluids. Special valving and connections between the treatment reservoir, the aforementioned tank and a supply container provides versatility and transfer of fluids under optimum conditions. For example, the fluid may be first introduced into the treatment reservoir from a supply container and then after treatment in the reservoir be transferred to the tank wherein the same serves as an insulating medium for electronic equipment; alternatively the fluid already in the tank may be treated by causing the same to enter the treatment reservoir for treatment after which the fluid is returned to such tank.

United States Patent [72] lnventor Wallace Dawson Loe Lakeside, Calif.[21] Appl. No. 779.074 [22] Filed Nov. 26, 1968 [45] Patented July13,1971 [73] Assignee Loe Industries [54] FLUlD-DEGASSING SYSTEM 6Claims, 1 Drawing Fig.

[52] US. Cl 55/189 [51] Int. Cl 801d 19/00 [50] FleldolSearch 55/l5,33,

[56] References Cited UNITED STATES PATENTS 2,147,677 2/1939 Smith 55/55X 2,562,972 8/1951 Wald 174/14 X 3,045,716 7/1962 Morgan et al.... 55/48X 3,238,574 3/1966 Martin et a1. 220/82 X 3,357,161 12/1967 Starr et a1.55/189 FOREIGN PATENTS 1,140,168 7/1957 France 220/82 PrimaryExaminerSamih N. Zaharna Assistant ExaminerR. W. Burks Attorney-Lyon &Lyon ABSTRACT: The system removes gases and moisture from dielectricfluids such as, for example, insulating oils normally used to provideelectrical insulation between electrical components in a tank filledwith such dielectric fluid. Degassing occurs in a treatment reservoirinto which the fluid is initially introduced and such degassing isaccomplished using a combination of vacuum and ultrasonic vibration andalso, in some instances, the fluid may be heated in the reservoir to asufficiently high temperature to assure efficient liberation of moisturefrom the fluids, Special valving and connections between the treatmentreservoir, the aforementioned tank and a supply container providesversatility and transfer of fluids under optimum conditions. Forexample, the fluid may be first introduced into the treatment reservoirfrom a supply container and then after treatment in the reservoir betransferred to the tank wherein the same serves as an insulating mediumfor electronic equipment; alternatively the fluid already in the tankmay be treated by causing the same to enter the treatment reservoir fortreatment after which the fluid is returned to such tank.

1 42A VENT UL 754 SON/C CUEZE/VT 501/566 FLUlD-DEGASSING SYSTEM Thepresent invention relates to the improved means and techniques fordegassing dielectric fluids.

Briefly, dielectric fluids initially supplied in a supply container 42may be transferred to a tank 40 in which they are ultimately used as aninsulating medium after being treated in a treatment reservoir undervacuum and ultrasonic vibration. Special valving and conduitsinterconnected with a vacuum pump 62 provide optimum fluid transferunder ideal conditions such as, for example, the fluid is notcontaminated by atmosphere during its transfer from the treatmentreservoir 10 to the tank 40 in which it is ultimately used.

The term degassing" has reference also to the removal of moisture underthose conditions wherein, for example, the fluid is heated to conditionthe moisture for removal by vacuum.

An object of the present invention is to provide improved means andtechniques whereby dielectric fluids are degassed and transferred underoptimum conditions.

A specific object of the present invention is to provide a system ofthis character in which a tank for dielectric fluids may be filled withsuch fluids either from an original supply container or by thedielectric fluid which was once in the tank and which requireddegassing.

The features of the present invention which are believed to be novel areset forth with particularity in the appended claims. This inventionitself, both as to its organization and manner of operation, togetherwith further objects and advantages thereof, may be best understood byreference to the following description taken in connection with theaccompanying drawings in which:

The single FIGURE of the drawing illustrates in schematic form thehydraulic and electrical equipment embodied in the present system.

The dielectric fluid is treated in a reservoir 10 referred to herein asa fluid treatment chamber, to which a vacuum may be applied via line 112simultaneously with the application of ultrasonic vibrations produced bythree ultrasonic transducers l4, l6, and lb acoustically coupled to thebottom tank wall 20.

The tank it) may be of rectangular construction with windows 2i and 22in opposite end walls of the same such that the light from a long lightbulb 24 may pass, in turn, through the window 211, through the fluid Fin tank 10, through the op posite window 22 and glass sight gauge 26.The general purpose of this optical arrangement is to allow a person toobserve the fluid level in tank 10 and also to observe the gas bubblesbeing formed at or near the bottom of the tank 10 and rising upwardlyfor removal by vacuum applied to the vacuum line 12.

The transducers 14, 16 and 18 are supplied with ultrasonic current fromthe source 30 which is effective when the onoff switch 32 is closed toapply the energizing voltage 34 to source 30. The energizing source 34has been shown as a DC source but, of course, this showing isdiagrammatic and the source may be an AC or a DC rectified source.

The tank 10 is connectable in a special manner to a fluid tank 60 or toa supply container 42 through corresponding fittings orconduit-connecting means 44, 46 and 47. Actually, in practice, theapparatus located between the fittings 44, 46 on the one hand and 47 onthe other hand, is mounted as a separate unit so as to be mobile and beconnectable to the tank so and/or supply container 42. For purposes ofthe present description, it will be assumed that the tank 60 has itsinlet and outlet 46A, 408 respectively connected to fittings 44 and 46herein referred to as conduit-connecting means and that the supplycontainer 32 has its outlet 42A connected to the fitting 47. The tank 40is representative of any container or housing of electronic equipment inwhich there is also present a dielectric fluid within which theelectronic equipment is immersed for insulation purposes. The fluid incontainer 42 may either be new fluid as originally supplied by amanufacturer or fluid reconditioned as described herein.

Fitting 47 is connected to the inlet 10A referred to herein as a fluidport, of tank 10 via valve 50 and a filter 52 such that fluid may enterthetank 10 through the fill line 54, valve 50, line 56, line 58, filter52 and line 60. During such filling operation the tank 10 may beevacuated using an electrically driven vacuum pump or vacuum-producingmeans, 62 which has its suction line 64 extending from vacuum port 62A,connectable to the tank opening 108 referred to herein as a vacuum port,via line 66, valve 68 and line 70. The pump 62 may have its pressureline 72 extending from discharge port 628 vented to the vent line 76 viacheck valve 78, line 80 and the two-position, three-way valve 82 whichis illustrated in its vent position. As illustrated, line 80 terminatesat a stationary port 80A and vent line 76 terminates at a stationarypoint 76A and the two ports 76A and 80A are communicated by the L-shapedchannel 84A in the movable or rotatable valve member 84. The valvemember 84 is rotatable from its position shown in the drawings to aposition 180 with respect to the same where the port 80A may then beplaced in communication with a stationary port 88A leading to a line 88whose function is later described.

The previously mentioned vacuum pump 62 may be operated by closing theon-ofi switch 90 to thereby apply current from the energizing source 92to the electrically driven pump 62.

Using the arrangement previously described, it will be seen that thereservoir 10 may be filled with fluid from container 42 by (1)connecting the supply container 42 to the reservoir fill line 54, (2)operating the valve 82 to its vent position shown in the drawings, 3)opening valves 50 and 68, (4) operating the vacuum pump 62 by closingswitch 90. During this filling operation the readings on the vacuumgauges 93 and 95 may be observed and checked to reassure that, forexample, a vacuum pressure of 21 inches of mercury pressure exists inlines 66 and 70, the gauge 93 being connected to line 66 and the gauge95 being connected to line 70. Also during this filling operation theliquid level in the tank may be continuously observed through the glasssight gauge 26 and when the fluid level reaches a desired amount, whichmay, for example, be somewhat less than 5 gallons valves 50 and 68 arethen closed and the vacuum pump 62 may be deenergized by opening switch90. Thus in this condition the treatment reservoir 10 is filled and incondition for degassing.

The fluid degassing process involves the following steps, namely:

l. energization of the sonic energy generator 30 by closing switch 32,

2. operating the vacuum pump 62 by closing switch 90,

3. opening valve 68, the valve 82 being still in its vent positionillustrated in the drawings,

4. the vacuum and sonic energy is thus supplied for a duration ofapproximately 30 minutes after which,

5. the valve 68 is closed and the switches 90 and 32 are then opened inthat order.

The next operation involves the transferring of the treated fluid fromthe reservoir 16 to the module or tank 40. This involves apparatus inaddition to that previously described and in general valves 160, 102,104, gauge 106 and overflow tube 108, and a vent line or airline 116which is in communication with the atmosphere through an air filter 112.One side of valve is connected to tank opening 10C via line 111 and theother side of valve W0 is connected to the vent line 110. Valve 1102 hasone side thereof connected to vacuum line 66 and the other side of valve102 is connected to line 114. A fixed orifice or restrictor 120 isinterposed between vent line and line 114. The pressure in line 114 maybe monitored by the vacuum gauge 106 which is connected to line 114.Valve H04 has one side thereof connected to line 114 and the other sideconnected to the overflow tube 108 via line 124. The other end ofoverflow tube R08 is connected to fitting 46.

Thus with the equipment described above flow is transferred from thetreatment reservoir 10 to the module or tank 40 in accordance with thefollowing procedure:

1. The fluid inlet tank opening 40A is connected to the fitting 44 andthe tank outlet 40B is connected to the other fitting 46,

2. the valve 100 is slowly opened until the reading on vacuum gauge 95begins to drop in which case air enters solely through the filter 112,the valve 100 being opened slowly to prevent breaking of surface tensionof the fluid in reservoir 10 and when the gauge 95 reads substantiallyzero the valve 100 is fully opened, and then 3. valves 102 and 104 areopened to thereby communicate the vacuum line 66 with the upper end oftank 40, valve 100 still remaining open, and then 4. switch 90 is closeto operate the vacuum pump 62, then 5. the readings on gauges 95 and 106are compared in which case the reading on gauge 95 may be in the rangeof to 1 inch of mercury pressure whereas the reading on gauge 106 may bein the order of 8 inch of mercury pressure, this difference in pressurebeing caused by the pressure drop across the fixed orifice 120, and thispressure drop is an indication that fluid is being drawn through thetank opening 10D and check valve 130 and fitting 44 to the fluid tankinlet 40A, and

6. the overflow tube 108 which is of clear glass is observed and whensuch tube 108 begins to fill the module or tank 40 is completely fulland thus the overflow tube condition serves as an indication that thevalves 102, 100 and 104 should be quickly closed in that order followedby a deenergization of the vacuum pump by opening switch 90.

It will be noted from the foregoing operation in which fluid istransferred to the module 40 that fluid enters the tube 108 and the nextstep described below involves the evacuation of the vacuum line andoverflow tube 108 which is essentially a transparent conduit. This isaccomplished in the following sequence, namely:

1. the flexible fluid line 140 and flexible vacuum line 142 aredisconnected from the tank 40 and the flexible vacuum line 142 isextended into a waste container, and then 2. valves 68 and 100 areopened, and then 3. valve 82 is operated to its other position to theso-called pressure" position wherein ports 80A and 88A areinterconnected by the L-shaped channel 84A thereby placing the line 124in communication with the vacuum pump pressure line 72 via check valve78, and then 4. the vacuum pump switch 90 is closed in which case thiscauses air to flow through filter 112, valve 100 and through opening 10Cto the top side of the reservoir 10, i.e. the vacuum side of the pump,through line 72 and through the check valve 78 and through line 82 toforce all residual fluid out of the overflow tube 108 and into the wastecontainer, and then 5. after all fluid has thus been blown out of theoverflow tube 108 and vacuum hose 142, the valve 82 is moved to itsvent" position illustrated in the drawings, and then the vacuum pumpswitch 90 is opened and then valves 68 and 100 are closed.

The apparatus described also allows transfer of fluid from the module ortank 40 to the degassing unit or reservoir 10 and this is accomplishedin the following sequence, namely:

1. The vacuum lines 142 and inlet line 140 are connected to the tank 40and then 2. valves 68, 104 and valve 200 are opened, the valve 200having one of its sides connected to the fluid line fitting 44 and theother one of its sides connected to the previously mentioned line 56 and58. At this stage it will be observed that the opening of valve 68places the top side of reservoir 10 in communication with the vacuumline 66, but the opening of valve 104 allows the topside of the moduleor tank 40 to be vented to the atmosphere through the orifice 120 andvent line 110 and filter 112, and that the opening of valve 200 placesthe tank inlet 40A in communication with the inlet side of the filter 52through which fluid may then flow into the bottom of tank 10 throughopening 10A, and then 3. the vacuum pump switch is closed, and then 4.the differentia reading between gauges i106 and is observed in whichcase the gauge 106 may read 7 inches to 8 inches of mercury pressure,whereas the gauge 95 may read 20 inches to 21 inches of mercurypressure, and then 5. the interior of reservoir i0 is observed for theappearance of large bubbles which do appear when the module 40 iscompletely empty. Of course, the capacity of the reservoir 10 is greaterthan the capacity of the tank 40, and then 6. valves 68, 104 and 200 areclosed in that order after which the vacuum pump switch 90 is opened.

It is noted that in the foregoing description of the five operations itwas assumed, as is the case, that all valves are originally closed andthat all valves, with the exception of valve 82, are on-off valves andthat valve 82 as previously described either communicates line 80 to theatmosphere or to line 88. Further, valve 82 is operated only during theoperation in which fluid is removed from overflow tube 108, and even inthat case valve 82 is initially in the vent position and after thatoperation is restored to its vent position.

Thus, it will be seen from the foregoing that fluid introduced fromsupply container 42 may be treated in reservoir 10 and then dischargedinto the module or tank 40. Alternatively, fluid in the module or tank40 may be introduced into the reservoir 10 where it is treated and thenreturned to the tank 40. ln each case the fluid is transferred undervacuum conditions and without opportunity for the oil to be contaminatedby ambient atmosphere.

While the particular embodiments of the present invention have beenshown and described, it will be obvious to those skilled in the art thatchanges and modifications may be made without departing from theinvention in its broader aspects and, therefore, the aim in the appendedclaims is to cover all such changes and modifications as fall within thetrue spirit and scope of this invention.

lclaim:

1. Apparatus for treatment of fluids including a fluid treatmentchamber, said chamber having a vacuum port located near the top of saidchamber; said chamber having a fluid port located near the bottom ofsaid chamber; an air line; first conduit-connecting means; means forcommunicating said air line with said first conduit-connecting means;second conduit-connecting means; means for communicating said fluid portwith said second conduit connecting means; said first conduit-connectingmeans and said second conduit-connecting means being connectable to afluid tank; vacuum-producing means; means communicating saidvacuum-producing means with said vacuum port; first valve means in saidmeans communicating said vacuum-producing means with said vacuum port;second valve means connected between said air line and saidvacuum-producing means and operable to intercommunicate said air linewith said vacuum-producing means; third valve means in said means forcommunicating said fluid port with said second conduit connecting means;additional means for communicating the bottom of said chamber with saidsecond conduit-connecting means; check valve means in said additionalmeans for preventing fluid flow from said second conduit-connectingmeans to the bottom of said chamber but allowing fluid flow from thebottom of said chamber to said second conduibconnecting means; and meansassociated with said chamber for degassing fluids contained therein, anenlarged transparent conduit in said means communicating said air linewith said first conduibconnecting means for sewing as an overflow; saidtransparent conduit having one of its ends connected to said firstconduit-connecting means and the other one of its ends connected to saidair line; said vacuumproducing means including a vacuum pump having avacuum port and a discharge port, said pump vacuum port beingconnectable with said chamber vacuum port; valve means connected betweensaid pump discharge pump and said transparent conduit for communicatingsaid pump discharge port either to the atmosphere or to that side of thetransparent conduit which is connected to said air line; andadditionalvalve means for intercommunicating the top of said chamberwith said airline.

2. Apparatus as set forth in claim 1 including a thirdconduit-connecting means for connection to a supply container,additional valve means the last mentioned valve means having one of itssides connected to said third conduit-connecting means and the other ofits sides in communication with said means communicating said secondconduit-connecting means with the bottom of said chamber.

3. Apparatus for treatment of fluids including: a fluid treatmentchamber; first conduit-connecting means; second conduitconnecting means;said first and second conduit-connecting means being connectablerespectively to the top and bottom of a fluid tank; thirdconduit-connecting means for connection to a fluid supply container;valve means for communicating said third conduit connecting means withthe bottom of said chamber; an air line; means communicating said airline with said first conduit-connecting means, means communicating thebottom of said chamber with said second conduitconnecting means;vacuum-producing means; valve means for communicating saidvacuum-producing means with the top of said chamber, valve means forintercommunicating said vacuum-producing means with said firstconduit-connecting means; and valve means for communicating the top ofsaid chamber with said air line; and valve means in said meanscommunicating said air line with said first conduit-connecting means, anenlarged transparent conduit in said means communicating said air linewith said first conduit-connecting means; said vacuum-producing meanscomprising a pump having a vacuum port and a discharge port; valve meansconnected between said vacuum port and the top of said chamber forcommunicating said vacuum port with said top of said chamber; valvemeans connected between said vacuum port and said air line forcommunicating said port with said air line; said transparent conduithaving a first end thereof connected to said first conduit-connectingmeans; and valve means connected between said discharge port and saidtransparent conduit for connecting said discharge port to either theatmosphere or to the other side of said transparent conduit.

4. Apparatus as set forth in claim 3 in which said means communicatingsaid second conduit-connecting means with the port of said chamberincludes a check valve for preventing flow in a direction from thesecond conduit-connecting means to said chamber; and additional valvemeans for communicat ing said second conduit-connecting means with thebottom of said chamber.

5. Apparatus as set forth in claim 2 in which said fluid treatmentchamber includes a pair of spaced transparent sidewalls and a bottom anda top; a light source adjacent one of said walls; liquid levelindicating means on the other of said walls; and means coupled to saidbottom for transmitting ultrasonic vibrations to the fluid in saidchamber for the formation of gas bubbles.

6. Apparatus as set forth in claim 2 including fluid filter meansthrough which fluid flows into said chamber either when fluid istransferred from said tank or from said supply container.

2. Apparatus as set forth in claim 1 including a thirdconduit-connecting means for connection to a supply container,additional valve means the last mentioned valve means having one of itssides connected to said third conduit-connecting means and the other ofits sides in communication with said means communicating said secondconduit-connecting means with the bottom of said chamber.
 3. Apparatusfor treatment of fluids including: a fluid treatment chamber; firstconduit-connecting means; second conduit-connecting means; said firstand second conduit-connecting means being connectable respectively tothe top and bottom of a fluid tank; third conduit-connecting means forconnection to a fluid supply container; valve means for communicatingsaid third conduit connecting means with the bottom of said chamber; anair line; means communicating said air line with said firstconduit-connecting means, means communicating the bottom of said chamberwith said second conduit-connecting means; vacuum-producing means; valvemeans for communicating said vacuum-producing means with the top of saidchamber; valve means for intercommunicating said vacuum-producing meanswith said first conduit-connecting means; and valve means forcommunicating the top of said chamber with said air line; and valvemeans in said means communicating said air line with said firstconduit-connecting means, an enlarged transparent conduit in said meanscommunicating said air line with said first conduit-connecting means;said vacuum-producing means comprising a pump having a vacuum port and adischarge port; valve means connected between said vacuum port and thetop of said chamber for communicating said vacuum port with said top ofsaid chamber; valve means connected between said vacuum port and saidair line for communicating said port with said air line; saidtransparent conduit having a first end thereof connected to said firstconduit-connecting means; and valve means connected between saiddischarge port and said transparent conduit for connecting saiddischarge port to either the atmosphere or to the other side of saidtransparent conduit.
 4. Apparatus as set forth in claim 3 in which saidmeans communicating said second conduit-connecting means with the portof said chamber includes a check valve for preventing flow in adirection from the second conduit-connecting means to said chamber; andadditional valve means for communicating said second conduit-connectingmeans with the bottom of said chamber.
 5. Apparatus as set forth inclaim 2 in which said fluid treatment chamber includes a pair of spacedtransparent sidewalls and a bottom and a top; a light source adjacentone of said walls; liquid level indicating means on the other of saidwalls; and means coupled to said bottom for transmitting ultrasonicvibrations to the fluid in said chamber for the formation of gasbubbles.
 6. Apparatus as set forth in claim 2 including fluid filtermeans through which fluid flows into said chamber either when fluid istransferred from said tank or from said supply container.